Fluid pressure brake apparatus



Nov. 12, 1957 T, MGCLURE Em 2,812,984

FLUID PRESSURE BRAKE APPARATUS Filed March 23, 1955 INVENTORS" 1 Cl arm"77 McClure BY John LU. Push www.m-

A T TOENE Y United States FLUID PRESSURE BRAKE APPARATUS ApplicationMarch 23, 1955, Serial No. 496,250

6 Claims. (Cl. 30335) This invention relates to fluid pressure brakeapparatus for railway cars, and more particularly, this inventionrelates to such apparatus for effecting a supply of fluid under pressurefrom an auxiliary reservoir or/ and an emergency reservoir to the brakecylinder on a railway car, for service and emergency brake applicationsthereon, responsively to service and emergency reductions, respectively,in pressure of fluid in a brake pipe, and for effecting release of suchfluid under pressure from the brake cylinder responsively to restorationof brake pipe pressure. An apparatus of the above general type may besuch as the well-known Westinghouse AB equipment, for example, orapparatus such as is disclosed in the corresponding United Statesapplication of Glenn T. McClure, Serial No. 357,984, filed May 28, 1953,and assigned to the assignee of the present application.

A prime object of the invention is to provide an improved fluid pressurebrake apparatus of the above type which incorporates means foraccelerating release of fluid under pressure from the brake cylinderresponsively to initiation in restoration of brake pipe pressurefollowing service and emergency brake applications.

Another object of the invention is to provide a fluid pressure brakeapparatus of the above type which incorporates means responsive toinitiation of brake pipe pressure restoration following a serviceapplication of the brakes on a railway car employing such apparatus, foreffecting local supply of fluid under pressure from the emergencyreservoir into the brake pipe on such car to hasten the build-up inpressure of fluid therein and thereby accelerate release of such serviceapplication.

Another object of the invention is to provide a fluid pressure brakeapparatus of the above type which includes a brake cylinder pressureretainer valve device which is positionable selectively to enable acomplete release of fluid under pressure from brake cylinder, or toretain a certain brake cylinder pressure or pressures upon release ofbrakes during cycling, and also includes means responsive to initiationof brake pipe pressure restoration following a service application ofthe brakes to effect supply of fluid under pressure from the emergencyreservoir to the brake pipe for acceleration of the brake release, onlywhen the retainer valve device is positioned for complete release of thebrakes.

Another object of the invention is to provide a fluid pressure brakeapparatus of the above type which includes means responsive toinitiation of brake pipe pressure restoration on a railway car employingsuch apparatus, for effecting local supply of fluid under pressure tothe brake pipe from the emergency reservoir following a serviceapplication of brakes on such car and from the brake cylinder and theauxiliary reservoir following an emergency application of such brakes,to hasten the build-up in pressure of fluid in the brake pipe andthereby accelerate release of the brakes following either type of brakeapplication.

Another object of the invention is to provide a fluid Wilt pressurebrake apparatus of the above type which includes a vent valve device foreffecting local venting of fluid under pressure from the brake pipe fromthe car employing such apparatus, and an accelerated release selectorvalve device to determine whether emergency reservoir or brake cylinderand auxiliary reservoir will be connected to the brake pipe foraccelerating the release of the brakes, and a valve device forcontrolling operation of the vent valve device and the acceleratedrelease selector valve device according to the type of brake applicationeffected. c

Other objects and advantages of the invention will become apparent fromthe following more detailed description thereof when taken in connectionwith the accompanying drawing in which the single figure is a schematicrepresentation of a fluid pressure brake apparatus embodying theinvention.

Description Referring to the drawing, the subject brake apparatusembodying the invention comprises a brake pipe 1, a brake cylinderdevice 2, an auxiliary reservoir 3, an emergency reservoir 4, and abrake controlling valve device 5 for controlling supply of fluid underpressure from the brake pipe 1 to the auxiliary and emergency reservoirs3 and 4 for charging same, for controlling supply of fluid underpressure from these reservoirs to the brake cylinder device 2responsively to reductions in pressure of fluid in the brake pipe 1, andfor controlling release of such fluid under pressure from the brakecylinder device 2 responsively to subsequent restoration in pressure offluid in said brake pipe.

Such apparatus on each car of a railway train is intended to be employedin conjunction with an engineers brake valve device (not shown) on thelocomotive of such train which is operable manually to a releaseposition to connect the brake pipe 1 extending throughout the length ofthe train to a source of fluid under pressure on the locomotive at apressure of such as seventy pounds per square inch; operable to aservice position for connecting the brake pipel at the locomotive to theatmosphere for release of fluid under pressure from said brake pipe at aservice rate; operable to an emergency position for connecting the brakepipe 1 at the locomotive to the atmosphere for releasing fluid underpressure therefrom at an emergency rate which is faster than saidservice rate; and operable to a lap position for closing off said brakepipe at the locomotive from the source of fluid under pressure on thelocomotive as well as from the atmosphere.

When the auxiliary and emergency reservoirs 3 and 4 in the fluidpressure brake apparatus on each car of the train are devoid of fluidunder pressure, the engineer on the locomotive will move the brake valvethereon to such as its release position for effecting supply of fluidunder pressure to the brake pipe 1 from the source of fluid at thechosen pressure of such as seventy pounds per square inch.

Such fluid under pressure as thus supplied to the brake pipe 1 will flowto a brake pipe passageway 6 in the brake controlling valve device 5 oneach car of the train, and such fiuid under pressure thence will flow tothe auxiliary reservoir 3 by way of a charging communication whichincludes said brake pipe passageway 6, a chamber 7 and curled hairstrainer 8 therein, a brake pipe passageway 9 and branches thereof, acharging choke 10, a brake pipe passageway 11, a port 12 in a slidevalve 13 in a service or triple valve portion 14 of the brakecontrolling valve device 5, a slide valve chamber 15 in said portion 14,and an auxiilary reservoir passageway and pipe 16 which is constantlyopen to said slide valve chamber 15 and to the auxiliary reservoir 3.

At the same time, fluid under pressure thus supplied from the brake pipe1 to the slide valve chamber via the above-traced chargingcommunication, will also flow to the emergency reservoir 4 by way of aport 17 in an auxiliary slide valve 18 in the service or triple valveportion 14, a registering port 19 in the slide valve 13 of said triplevalve portion, and an emergency reservoir pipe and passage 29 which isin constantly open communication with said emergency reservoir 4.

The auxiliary and emergency reservoirs 3 and 4 in the brake apparatus oneach car on the train will thus be charged from the brake pipe 1 by wayof the above-traced charging communications in the respective brakecontrolling valve devices 5 on such cars to a normal brake pipe pressurevalue of such as seventy pounds per square inch, thereby rendering suchbrake apparatus capable of etfecting supply of fluid under pressure tothe respective brake cylinder devices 2 for applying-brakes on suchcars.

The brake cylinder device 2 on each car of the train comprises the usualpiston 21 adapted for operative connection with the usual brake rigging(not shown) through the medium of the usual push rod (not shown), andsuch piston is subject opposingly to pressure of fluid in the usualbrake cylinder pressure chamber 22 and to. force or" a return spring 23.During the initial charging of the auxiliary and emergency reservoirs 3and 4 as described above, and subsequently so long as the pressure offluid in the brake pipe 1 remains at its normal full charge value ofsuch as seventy pounds, the brake cylinder pressure chamber 22 will bevented to the atmosphere by way of an unrestricted exhaust communicationwhich includes a brake cylinder pipe and passageway 24, a chamber 25 inan inshot and quick service limiting portion 26 of the brake controllingvalve device 5, an unseated check valve 27 also in said inshot and quickservice limiting portion, a passageway 28, a cavity 29 in the slidevalve 13 of the service or triple valve portion 14 in its releaseposition at this time, a passageway and pipe 30, an inlet port 31 in aretainer valve device 32, a port 33 in anangle cock 34 of said devicewhen positioned as shown in the drawing for full release of the brakes,and an exhaust port 35 also in device 32. With brake cylinderpressurechamber 22 thus vented to the atmosphere and when thereforedevoid of fluid under pressure, the return spring 23 will maintain thebrake cylinder piston 21 in its release position in which it is shown inthe drawing, for release of the brakes on the respective car.

Service application of the brakes For sake of illustration, the serviceor triple valve portion 14 of each brake controlling valve device 5comprises a diaphragm-piston 36 which is operatively connected to aslide valve stem 37 for actuating slide valves 13 and 18. The diaphragmpiston 36 is subject opposingly to pressure of fluid in a brake pipepressure chamber 38 at one side and to auxiliary reservoir pressure inthe slide valve chamber 15 at its opposite side; said brake pipepressure chamber 38 being in constantly open communication with thebrake pipe 1 by way of a branch of the brake pipe passageway 9, strainerchamber 7, and brake pipe passageway 6.

When pressure of fluid in the brake pipe 1 is reduced at a service rateby virtue of manipulation of the brake valve on the locomotive toservice position, such reduction in brake pipe pressure as experiencedin chamber 38 in the service or triple valve portion 14 of each brakecontrolling valve device 5 on the respective cars of the train willcause the resultant preponderant auxiliary reservoir pressure in slidevalve chamber 15 backed up by charging choke 10 to actuate, through themedium of a shoulder 39 on stem 37, the auxiliary slide valve 18upwardly, as viewed in the drawing, relative to the slide valve 13 to aquick service position in which the auxiliary reservoir charging port 12and emergency reservoir charging port 19 in the slide valve 13 areblanked off by said auxiliary slide valve and a quick service cavity 40is brought into registry with ports 41 and 42 in the slide valve 13 forconnecting the brake pipe 1 to a quick service volume 43 vented to theatmosphere by a leak choke 44, by way of the brake pipe passageway 6,strainer chamber 7, brake pipe passageway 9, a choke 45, said port 41,said quick service cavity 40, said port 42, and a passageway 46. In theWell-known manner, such connection of the brake pipe 1 to the quickservice volume 43 permits a quantity of fluid under pressure to rapidlyflow locally from the brake pipe to fill such volume and thereby etiecta rapid local reduction in brake pipe pressure which is propagatedserially back through the train by corresponding quick servicereductions in brake pipe pressure as effected by the respective brakecontrolling valve devices 5 on the various succeeding cars thereof.

The initial quick service position of the auxiliary slide valve 18relative to the main slide valve 13 is defined by engagement of ashoulder 47 formed in a slide valve stem 37 with a shoulder 48 formed inthe lowermost end of said slide valve 13 as viewed in the drawing. Insuch preliminary quick service position of the auxiliary slide valve 18,one end of a brake cylinder service supply port 49 in the main slidevalve 13 is uncovered to the slide valve chamber 15 in the triple valveportion and thereby to the auxiliary reservoir. After the sudden, local,quick service reduction in brake pipe pressure has been effected by theflow of fluid under pressure to the quick service volume 43, quickservice reduction in brake pipe pressure continues at a slower rate byflow through the choke 44 for the purpose of insuring obtaining asufiicient reduction in brake pipe pressure below auxiliary reservoirpressure acting on opposite sides of the diaphragm piston 36 to causesaid diaphragm piston to move the main slide valve 13 through the mediumof the stem 37 and shoulders 47 and 48 to a service position in which:the opposite end of the service supply port 49 is connected to the brakecylinder passageway 28 for supply of fluid under pressure to the brakecylinder device 2, as will be traced subsequently; the port 41 in themain slide valve 13 is moved out of registry with the brake pipepassageway 9 via choke to terminate the preliminary quick serviceventing of fluid under pressure from the brake pipe to the quick servicevolume 43 and choke 44; and, a secondary quick service cavity 50 isbrought into registry with said brake pipe passageway 9 via choke 45 forcontinued quick service withdrawal of fluid under pressure from thebrake pipe 1 to the brake cylinder device, as will be tracedsubsequently.

Immediately upon registry of the service supply port 49 in the mainslide valve 13 with brake cylinder passageway 28 with movement of saidslide valve to its service position, fluid under pressure from theauxiliary reservoir 3 will flow to brake cylinder pressure chamber 22 inbrake cylinder device 2 preponderantly by way of pipe and passageway 16,the slide valve chamber 15 and said brake cylinder supply port 49 in theservice or triple valve portion 14, the brake cylinder passageway 28,the unseated check valve 27 in the inshot and quick service limitingportion 26 of the brake controlling valve device 5, the chamber 25 alsoin said portion 26, and the pipe and passageway 24 to the brake cylinderdevice. Such flow of fluid under pressure to the brake cylinder pressurechamber 22 from the auxiliary reservoir 3 to the brake cylinder device 2via the communication traced above will,occur at a relatively rapid ratesince such flow path is substantially without restriction. At the sametime, some auxiliary reservoir fluid supplied to the brake cylinderpassageway 28 as traced above will also flow to the brake cylinderpressure chamber 22 at a restricted rate from said passageway 28 via theusual inshot bafl'le choke 51, a brake cylinder passageway 52, a chamber53 in a brake cylinder vent valve portion 54 in a brake cylinder releaseand reapplication valve device 55, and a branch of the brake cylinderpassageway and pipe 24; the brake cylinder release and reapplicationvalve device, 55 forming no part of the present invention except insofaras bafile-choke-supply to the brake cylinder device occurs via the brakecylinder vent valve portion 54 thereof.

In the usual manner, upon establishing registry of the secondary quickservice cavity 50 with brake pipe passageway choke 45 by movement of themain slide valve 13 to its service position as previously described,flow of fluid under pressure from the brake pipe 1 will continue to bewithdrawn locally to the brake cylinder device 2 by way of brake pipepassageway 6; connected brake pipe 1; the strainer chamber 7; the brakepipe passageway 9; the quick service limiting choke 45; said cavity 50;a secondary quick service passageway 56; a spring-biased check valve 57and a chamber 58 in the inshot and quick service limiting portion 26 ofthe brake controlling valve device a spring-biased check valve 59 heldunseated by a control spring 60 in said portion 26 through the medium ofa diaphragm piston 61 and abutting stern assemblage 62, 63; a port 64;the chamber 25; and the brake cylinder passageway and pipe 24. It willbe noted here that the check valve 57 in the inshot and quick servicelimiting portion 26 of the brake controlling valve device 5 operates toprevent backflow of fluid under pressure from the brake cylinder device2 to the brake pipe 1 should the pressure of fluid in the brake pipe 1be reduced to atmospheric pressure or to pressures lower than thoseexistent or that existent in the brake cylinder, such for example, aswhen said brake pipe is completely vented to the atmosphere to eifect anemergency application of the brakes, which will hereinafter bedescribed.

As fluid under pressure is supplied from the service or triple valveportion 14, as above-described, to the brake cylinder device 2 via thebrake cylinder passageway 28, a portion of such fluid under pressurewill also flow from said passageway 28 by Way of a stabilizing choke 65and a brake cylinder passageway 66 to a brake cylinder pressure chamber67 at one side of the diaphragm piston 61 in the inshot and quickservice limiting portion 26, to oppose action of the control spring 60on said diaphragm piston. When a certain brake cylinder pres- .sure,such as ten pounds per square inch, is realized in the brake cylinderpressure chamber 67 in the inshot and quick service limiting portion 26as a result of supply of fluid under pressure from the auxiliaryreservoir 3 to the brake cylinder device 2 via the service or triplevalve portion 14 as above described, such pressure in the brake cylinderpressure chamber 67 will eflect movement of the diaphragm piston 61 topermit the springbiased check valves 27 and 59 to seat and therebyterminate subsequent and unrestricted supply of fluid under pressure tothe brake cylinder device 2 and terminate secondary flow of quickservice withdrawal of fluid under pressure from the brake pipe 1 to thebrake cylinder device 2 via the chamber 25 in said inshot and quickservice limiting portion 26.

After the check valves 27 and 59 in the inshot and quick servicelimiting portion 26 of the brake controlling valve device 5 close asabove to prevent further unrestricted supply of fluid under pressure tothe brake cylinder device 2 and to prevent further local quick servicewithdrawal of fluid under pressure from the brake pipe 1, pressure offluid in brake pipe 1 will continue to reduce by way of the engineersbrake valve device on the locomotive while in its service position untilthe desired degree of service reduction has been attained, after whichthe engineer will move the brake valve to its lap position to retain thedesired degree of brake pipe pressure as attained by manipulation of thebrake valve. Meanwhile, the service or triple valve portion 14 in thebrake controlling valve devices 5 on each car of the train will remainin service position to continue supply of fluid under pressure to thebrake cylinder pressure chamber 22 in the brake cylinder device 2 at acontrolled rate by way of the service supply port 49 in the main slidevalve 13 of said portion 14, the brake cylinder passageway 28, theinshot bafile choke 51, the passageway 52, etc., as previously traced.

As a result of such supply of fluid under pressure from the auxiliaryreservoir 3 to the brake cylinder device 2 by Way of the service ortriple valve portion 14, the pressure of fluid in the auxiliaryreservoir will reduce, and such reduction will be experienced in theslide valve chamber 15 of said portion 14. When the auxiliary reservoirpressure in the slide valve chamber 15 in triple valve portion 14reduces slightly below brake pipe pressure existent in the chamber 38,the diaphragm piston 36 in said portion 14 will move in the direction ofsaid chamber 15 and, through the medium of the slide valve stem 37 and ashoulder 68 therein in abutment with the auxiliary slide valve 18, Willefiect movement of said auxiliary slide valve relative to the main slidevalve 13 to a lap position defined by engagement of a shoulder 69 insaid stem 37 with the upper end of the main slide valve 13 as viewed inthe drawing. The engagement of shoulder 69 in the slide valve stem 37with the upper end of the main slide valve 13 at this time preventsfurther downward movement of the triple valve assemblage and definesWhat is commonly known as a service lap position in which the auxiliaryslide valve 18 laps the service port 49 to thereby prevent further flowof fluid under pressure from the auxiliary reservoir 3 to the brakecylinder pressure chamber 22 in the brake cylinder device 2 and therebylimit the pressure of fluid attained therein in accordance with theservice reduction in brake pipe pressure.

As a result of such supply of fluid under pressure to the brake cylinderpressure chamber 22 in the brake cylinder device 2 as described above,the piston 21 therein will be moved against opposition of the returnspring 23 to actuate the push rod (not shown) to take up the slack inbrake rigging (not shown) and advance the brake shoes (not shown) intoengagement with the wheels of the railway car and to effect anapplication of the brakes on such wheels according to the degree ofpressure in said chamber 22 and hence in accord with the degree ofservice reduction in pressure of fluid in the brake pipe 1.

If a further service reduction in pressure of fluid in the brake pipe 1is effected for increasing the degree of service application of thebrakes, in the brake controlling valve device 5 on each car of thetrain, the diaphragm piston 36 will move in the direction of chamber 38responsively to such further reduction of brake pipe pressure therein toactuate the auxiliary slide valve 18 out of its lap po sition toreestablish communication between the main slide v-alves service port 49and the slide valve chamber 15 for supply of fluid under pressure fromthe auxiliary reservoir 3 to the brake cylinder device 2 to increase thepressure of fluid therein to a value commensurate with the furtherreduction in brake pipe pressure, as will be apparent from the foregoingdescription. Subsequently, the resultant reduction in auxiliaryreservoir pressure as experienced in the slide valve chamber 15 in theservice or triple valve portion 14 of the brake controlling valve device5 will cause the diaphragm piston 36 to return the auxiliary slide valve18 to its lap position for holding the desired brake cylinder pressure.

From the foregoing it will be apparent that on each car of the train theauxiliary and emergency reservoirs 3 and 4 will be charged with fluidunder pressure from brake pipe 1 by way of a charging communication orcommunications under the control of the service or triple valve portion14 of the respective brake controlling valve device 5, and that thedegree of brake cylinder pressure in chamber 22 in the correspondingbrake cylinder device 2, hence the degree of service application of thebrakes, as effected by supply of fluid under pressure thereto from theauxiliary reservoir 3, is controlled by the service or triple valveportion 14 and the inshot and quick service limiting portion 26 of suchbrake controlling valve device according to the degree of reduction inbrake pipe pressure. s

As shown in the drawing, the brake cylinder device 2 is of a loadcompensating type which comprises a load compensating pressure chamber70 adapted to be supplied with fluid under pressure by way of a loadcompensating portion 71 (shown in outline) of the brake controllingvalve device by Way of a pipe and passageway 72 to partially neutralizethe brake" applying eflect of fluid pressure in the chamber 22 on thepiston 21 according to the load carried on the vehicle. Also shown inthe drawing in outline is a known form of strut cylinder device 73 whichis operatively connected to the load cornpensating portion 71 of valvedevice 5 by way of such as pipe and passages 74- to condition saidportion 71 according to the degree of the load carried by the car. Sincethe load compensating portions of the equipment form no portion of thenovel aspects of applicants invention, further description of suchportions is omitted herein.

Emergency application of the brakes In efiecting an emergencyapplication of the brakes, the engineers brake valve device on thelocomotive will be moved to emergency position to connect the brake pipeon the locomotive locally to the atmosphere for complete release offluid under pressure and at a faster rate than transpires when saidbrake valve device is in service position. A resultant reduction inpressure of fluid will be experienced in the brake pipe 1 on the firstcar of the train, and this reduction in brake pipe pressure will beexperienced in the brake pipe pressure chamber 38 in the service ortriple valve portion 14 of brake controlling valve device 5 on such carand will cause same to consecutively assume its quick service andservice positions for effecting local withdrawal of fluid under pressurefrom the brake pipe and supply of fluid under pressure from theauxiliary reservoir 3 to the brake cylinder pressure chamber 22 in thebrake cylinder device 2 as set forth previously herein. At the sametime, such reduction in pressure of fluid in the brake pipe 1 will beexperienced also by way of the brake pipe passageway 6, in a brake pipepressure chamber 75 in an emergency application control portion 76 ofthe brake controlling valve device 5. As a result of such emergencyreduction in brake pipe pressure as experienced in the brake pipepressure chamber 75 in the emergency application control portion 76, adiaphragm piston 77 in said portion 76 will be moved in the direction ofsaid chamber 75 against opposition of a cage and return springassemblage 78 by preponderant pressure of fluid in a chamber 79 which isconstantly open by way of a passageway 80 to a quick action chamber 81normally charged from the brake pipe 1 by way of a quick action chambercharging choke 82, the brake pipe passageway 9, the strainer chamber 7,and the brake pipe passageway 6. Such movement of the diaphragm piston77, through the medium of a slide valve stem 83, effects movement of aslide valve 84 to a position for registration of a port 85 therein,constantly open to chamber '79, with a passageway 86 to permit fluidunder pressure to flow from said chamber 79 and the quick action chamber81 open thereto to a control chamber 87 at one side of a diaphragmpiston 88 in an emergency vent valve portion 89, and via a choke 90 anda passageway 91 to a control chamber 92 in a high pressure valve portion93.

The opposite side of the diaphragm piston 88 in the emergency vent valveportion 89 is exposed to a nonpressure chamber 94 which is constantlyopen to the atmosphere by way of an exhaust passageways 95, and a largecapacity vent passageway 96 open to the atmosphere via a resilient dustexcluded 97 associated therewith, so that the supply of fluid at normalbrake pipe or quick action chamber pressure to the chamber 87 in theemergency vent valve portion 89 will cause movement of the dia- 8 tphragm piston 88 in the direction of the chamber 94 to unseat, throughthe medium of a stem 98, a vent valve 99 against opposition of acompression spring 100 disposed in a brake pipe pressure chamber 101..Immediately upon unseating of the vent valve 99, a sudden, largecapacity emergency venting flow of fluid under'pressure from the brakepipe 1 to the atmosphere will occur by way of the brake pipe passageway6, the brake pipe pressure chamber 101 and the unseated valve 99 in theemergency vent valve portion 89, the vent passageway 96 and the dustexcluder 97. As a result of such local withdrawal of fluid underpressure from the brake pipe 1 by way of the emergency vent valveportion 89 of the brake controlling valve device 5 on the respectivecar, an emergency reduction in brake pipe pressure is transmitted to thebrake controlling valve device 5 on the following car in the, train and,by virtue of corresponding operation of the emergency vent valve portion89 of the brake controlling valve device thereon, such reduction will betransmitted at a rapid rate serially from car to car throughout thelength of the train, in the usual manner.

At the same time, the fluid at quick action chamber pres sure in thecontrol chamber 92 in the high pressure valve portion 93 is suppliedthereto by the emergency application control portion 76 as describedabove, will cause movement of a piston valve 102 in said portion 93against opposition of the rapidly reducing brake pipe pressure inchamber 101 to a position in the direction of said chamber 101 definedby engagement of the lowermost end of said piston valve with a fixedstop 103 to establish registry of a groove 104 in said piston valve withbranches of the emergency reservoir passageway 20 and brake cylinderpassageway 28. Upon the piston valve 102 thus being caused to assume itsemergency supply position, fluid under pressure from the emergencyreservoir 4 will flow to the brake cylinder pressure chamber 22 in thebrake cylinder device 2 for added pressurization thereof above thatrealized by virtue of triple-valve-admitted auxiliary reservoir fluid,by way of said pipe and passageway 20, the groove 104 in said pistonvalve 102, the previously-mentioned branch of the brake cylinderpassageway 28, the inshot baffle choke 51, the brake cylinder passageway52, the chamber 53 in the brake cylinder vent valve portion 54 of thebrake cylinder release and reapplication valve device 55, and the brakecylinder passageway and pipe 24' Perhaps momentarily such supply offluid under pressure fro-m the emergency reservoir 4 to the brakecylinder pressure chamber 22 in the brake cylinder device 2 by way ofthe brake cylinder passageway 28 will flow in by-pass of inshot bafllechoke 51 by way of respective branch of said passageway 28, the checkvalve 27 in the inshot and quick service limiting portion 26, whenunseated, the chamber 25 therein, the brake pipe passageway and pipe24-. Since, however, pressure of fluid in the brake cylinder pressurechamber 22 in the brake cylinder device 2 will be built up at arelatively rapid rate by virtue of flow of fluid under pressure theretofrom both the auxiliary reservoir 3 and the emergency reservoir 4, andby virtue of the relatively rapid rate of reduction in brake pipepressure experienced in the brake controlling valve device 5 as a resultof operation of the emergency vent valve portion 89 as above described,the brake cylinder pressure as realized in chamber 67 in the inshot andquick service limiting portion 26 via passageway 66, choke 65,passageway 23 etc., Will cause rapid closure of check valve 27 duringthe early stages of effecting an emergency application of the brakes,and subsequent brake cylinder supply will transpire exclusively by wayof the inshot baffle choke 51.

From the foregoing it will be apparent that during the effecting of anemergency application of the brakes, in the usual manner, the pressureof fluid in the brake pipe will be reduced to that of the atmospherewhile pressure of fluid in the auxiliary reservoir 3, emergencyreservoir 4, and brake cylinder pressure chamber 22 equalize at somesuch pressure as sixty pounds per square inch. In each brake controllingvalve device 5, the preponderant effect of of auxiliary reservoirpressure at such as sixty pounds per square inch in the slide valvechamber 15 in the service or triple valve portion 14 at one sideofdiaphragm piston 36 over atmospheric pressure in the brake pipepressure chamber 38 at the opposite side of said diaphragm piston 36will maintain the main slide valve 13 and auxiliary slide valve 18 intheir service positions connecting the brake cylinder pressure chamber22in the brake cylinder device 2 to the auxiliary reservoir 3 by way ofthe brake cylinder passageway 28, the service part 49 of said slidevalve 13, the slide valve chamber 15 ofsaid triple valve portion 14, andtheauxiliary reservoir passageway and pipe 16, as will be appreciatedfrom previous description of operation of such service valveportion.

At the same time, subsequent to reduction in pressure of fluid in thebrake pipe 1 to that of the atmosphere, via port 85 in slide valve 8401the emergency application control portion 76, fluid underpressure fromthe quick action chamber 81 and connected chamber 79 in said emergencyapplication control portion 76, as well as chamber 87 in the emergencyvent valve portion 89, and, via passageway 91 and choke 90, the chamber92, in the high pressure valve portion 93 will dissipate to theatmosphere by way of the passageway 86, a dissipation timing choke 105,a central passageway 106 in a stem type slide valve 107 attached todiaphragm piston 88, and a port 108 opening from an extension of saidpassageway 106 in the stem 98 which opens into the large capacity ventpassageway 96.

Dissipation of fluid under pressure from chamber 87 in the emergencyvent valve portion 89 by way of the timing choke 105 as set forth above,will permit the compression spring 188 to reseat the vent valve 99 toclose off the brake pipe passage 6 to the atmosphere via passageway96-and thereby permit subsequent pressurization of the brake pipe forrelease of the brakes as will be described in detail hereinafter.Through the medium of the stem 98, such closure of the vent valve 99also causes actuation of the stem type slide valve 107 to the positionin which it is shown in the drawing for connecting the chamber 87 toatmosphere additionally by way of a casing port 109 and a registeringport 110 open to the central passageway 106 in said slide valve 107,said passageway 1'06, the port 108, and the large capacity ventpassageway 96. By virtue of the additional venting communication of thechamber 87 to the atmosphere by way of ports 1'09 and 110 as well as byway of passageway 86, timing choke 105, passageway 106, etc., ample flowcapacity is provided for dissipation of any fluid under pressure fromthe chamber 79 in the emergency application control portion 76 which mayleak into chamber 87 via passageway 86 past the slide valve '84 when inits lap position in which it is shown in the drawing and which positionit is caused to assume-as will be described subsequently. Thus it willbe apparent that leakage of fluid under pressure to the chamber :87 willbe incapable or effecting unintended movement of the emergency valveportion 89 to its vent position.

As fluid under pressure is vented from the chamber 79 in theemergencyapplication control portion 76 by way of the port 85 in the slide valve'84 thereof, the passageway 86, the timing choke 185, and the passageway186 in the slide valve 107 and stem 98 in the emergency vent valveportion 89 as described above, such venting will sufliciently reducethepressure of fluid insaid chamber 79 to permit the cage and return springassemblage 78, by virtue of its engagement with a casing shoulder 111,to move the slide valve 84 to a service position in which the port 85open to chamber 79 is blanked oii from the passageway 86 and a vent port112 also open to said chamber 79 is brought into registry with a choke113 constantly open to an exhaust passageway 114 connected to the largecapacity vent passageway 96, whereupon, fluid under pressure from thechamber 79 .and connected quick action chamber 81 will continue toreduce to the atmosphere by way of said port 112, choke 113, passageway114, and vent passageway 96. The slide valve 84 in the emergencyapplication control portion 76 will remain in such position with itsvent port 112 in registry with the choke 113 and the cage and returnspring assemblage 78 in abutment with casing shoulder 111 subsequent toreduction of pressure of fluid in the chamber 79 to that of theatmosphere, so long as brake pipe pressure in chamber 75 remains atatmosphere pressure.

In the emergency application control portion 76, during the efiecting ofa service application of the brakes by the service or triple valveportion 14 as previously described, the pressure of fluid in the chamber79 and connected quick action chamber 81, charged from the brake pipe byway of the choke 82, will preponderate over the brake pipe pressure inchamber 75 while reducing at its service rate. Such rate of reduction inbrake pipe pressure in chamber 75 will occur at a faster rate than anyreduction in quick action chamber pressure which may be experienced as aresult of flow of fluid under pressure from chamber 79 and quick actionchamber 81 by way of the supply choke 82, with the result that pressureof ffuid in the chamber 79 moves the diaphragm piston 77 in thedirection of the brake pipe pressure chamber 75 to cause the cage andreturn spring assemblage 78 to abut the casing shoulder 111 and, throughthe medium of the slide valve stem 83, moves the slide valve 84 to itsposition for establishing registry of its port 112 with vent choke 113for venting of said chamber 79, hence the quick action chamber 81, tothe atmosphere by way of said choke 113 and the exhaust passage 114.With such release of quick action chamber fluid from chamber 79 viachoke 113 and passageway 114 to the atmosphere, the reduction in quickaction chamber pressure in chamber 79 will render such pressure actingon diaphragm piston 77 incapable of overcoming opposition of the cage.and return spring assemblage 7 8 and of the service-rate-reducing brakepipe pressure in chamber 75 acting on the diaphragm piston 77, so that,during service reductions in brake pipe pressure, said diaphragm pistonis prevented from moving the slide valve 84 to its emergency position toconnect port 85 to passageway 86 for effecting operation of the vent andhigh pressure valve portions 89 and 93 as previously described. Thus itwill be appreciated that during the effecting of a service applicationof the brakes by service reductions in brake pipe pressure, by virtue ofthe venting action of fluid under pressure from the chamber 79 via theport 112 in the slide valve 84 of the emergency application controlportion 76, the chamber 92 in high pressure valve portion 93 will remaindevoid of fluid under pressure while the piston valve 102 in saidportion 93 remains in its uppermost position in which it is shown in thedrawing to prevent supply of fluid under pressure from the emergencyreservoir to the brake cylinder, and the vent valve 99 in the emergencyvent valve portion 89 remains closed in absence of pressurization ofchamber 87.

Triple valve operation during release of the brakes following serviceand emergency brake applications Following a service application of thebrakes, the diaphragm piston 36 in the service or triple valve portion14 will respond to establishment of preponderance in brake pipe pressurein its chamber 38 over auxiliary reservoir pressure in its chamber 15,and, in the Wellknown manner, through the medium of shoulders 69 and 68in the slide valve stem 37 attached to said diaphragm piston, will movethe main slide valve 13 and auxiliary slide valve 18 to their releasepositions in which they are shown in the drawing, defined by engagementof the lowermost end of said stem with the casing, to again establishregistry of the brake cylinder passageway 28 with the exhaust passageway30 for release of fluid under pressure from the brake cylinder 11pressure chamber 22 in brake cylinder device '2 byway of the pipe andpassageway 24, chamber 53 in the brake cylinder vent portion 54 of thebrake cylinder release and reapplication valve device 55, the brakecylinder passage 52, the inshot bafiie choke 51, brake cylinderpassageway 28, the groove 29 in the slide valve 13 of said service ortriple valve portion, said exhaust passageway 30, thence to theatmosphere by way of the brake cylinder retainer device 32. Such releaseof the brakes will occurat a rate controlled by the inshot baffle choke51 until brake cylinder pressure as realized in the control chamber 67in the inshot and quick service limiting portion 26 via passageway 66,stabilizing choke 65 and a branchof the brake cylinder passageway 28,reduces below the chosen value of such as ten pounds per square inch,whereupon, the spring 60 in said portion 26 will effect movement of thediaphragm piston 61 and stem assemblage 62, 63 to open the check valve27 for permitting subsequent relatively unrestricted release of fluidunder pressure from the brake cylinder pressure chamber 22 in by-pass ofthe inshot baflle choke 51 by Way of said brake cylinder passageway 24,the chamber 25 in said portion 26, the unseated check valve 27, thebrake cylinder passageway 28, the groove 29 in the slide valve 13 of theservice or triple valve portion 14, the exhaust passageway and pipe 30,and the brake cylinder retainer device 32. At thesame time that checkvalve 27 in the inshot and quick service limiting portion 26 is unseatedas above described, the check valve 59 will also be unseated to permitcontinued quick service activity to .be realized upon the subsequenteflecting of a service application of the brakes as previouslydescribed.

Upon release of the'brakes following an emergency application thereof,the service or triple valve portion 14 will respond to a slightpreponderance of such as a fraction of a pound in brake pipe pressure inchamber 38 over auxiliary reservoir pressure in chamber 15 to cause theauxiliary slide valve 18 to move relative to the main slide valve 13 toits lap position for closing off the service port 49 in valve 13 to theslide valve chamber 15, thereby disconnecting the auxiliary reservoirfrom the brake cylinder via said chamber 15, said service port 49, andthe brake cylinder passageway 28 which yet remains connected to saidservice port. Subsequently, upon establishment of a greater degree ofpreponderance, such as several pounds, in brake pipe pressure in chamber38 over auxiliary reservoir pressure in chamber 15, diaphragm piston 36will actuate stem 37 to move slide valve 13 and auxiliary slide valve 18to assume their release positions in which they are shown in the drawingfor release of fluid under pressure from the brake cylinder pressurechamber 22 in the brake cylinder device 2 in the same manner asdescribed above in connection with release of brakes in a serviceapplication, bearing in mind that during a service application theservice or triple valve portion will be in its lap position, whereasduring an emergency application of the brakes, said service or triplevalve portion 14 remains in its service application position in whichthe brake cylinder is connected to the auxiliary reservoir by way of thebrake cylinder passageway 28, and main slide valve service port 49uncovered to the slide'valve chamber 15 by virtue of the position of theauxiliary slide valve 18 relative to main slide valve 13. Suchapplication position of the service or triple valve portion 14 ismaintained during an emergency application of the brakes by virtue ofthe preponderant effect of auxiliary reservoir pressure in the slidevalve chamber 15 at one side of the diaphragm piston 36 over theatmospheric brake pipe pressure in chamber 38 at the opposite side ofsaid diaphragm piston. It will also be appreciated in View of previousdescription in connection with initial charging of the equipment, thatupon return of the slide valves 13 and 18 to their release position inwhich they are shown in the drawing responsive to establishment of thenecessary degree of preponderance in brake pipe pressure in chamber 38over auxiliary reservoir pressure in slide valve chamber 15, followingeither a service or an emergency application of the brakes, rechargingof the auxiliary reservoir 3 or/and the emergency reservoir 4 for makeupof any pressure deficiency therein created as a result of supply to thebrake cylinder device 2 will occur by way of the charging ports 12, 17and 19 in slide valves 13 and 18, the slide valve chamber 15 etc.

Such release of fluid under pressure from the brake cylinder pressurechamber 22 at one side of the piston 21 in the brake cylinder device 2will permit the return spring 23 to move said piston in the direction ofsaid pressure chamber 22 to relieve the force applied to the brakerigging and thereby release the application of brakes on the car.

Description of accelerated release control portion of the brakeapparatus According to a feature of the invention, the brake controllingvalve device 5 comprises an accelerated release selector valve portionfor controlling communication selectively between the input chamber 116to an accelerated release control check valve 117 and either theemergency reservoir 4 or the brake cylinder device 2 and the auxiliaryreservoir 3 by Way of a passageway 118, according to whether a serviceapplication or an emergency application of the brakes, respectively, hasbeen elfected. The accelerated release selector valve portion 115comprises a piston valve 119 slidably mounted in a bore 120 and exposedat one end to a chamber 121 which is constantly open to the quick actionchamber 81 by way of passageway 80, and at its opposite end to anon-pressure chamber 122 which is constantly open to the atmosphere byway of a port 123. The piston valve 119 is provided with a pair ofaxially spaced-apart grooves 124 and 125 formed in its outer peripherywhich cooperate with the wall of bore 120 to control selectivecommunication of the passageway 118 with either a branch of brakecylinder passageway 28 or a branch of the emergency reservoir passageway20. The piston valve 119 is urged in the direction of the pressurechamber 121 to an accelerated emergency release position in which it isshown in the drawing, defined by engagement of the uppermost end of saidpiston valve with a casing shoulder 126, by a compression spring 127disposed in a chamber 128, as well as by any pressure of fluid which mayexist in said chamber, through the medium of a diaphragm piston 129 anda stem 130 attached to said piston valve. The diaphragm piston 129 issubject opposingly to pressure of fluid in the non-pressure chamber 122at its one side and to pressure of fluid and force of the spring 127 atits opposite side. The chamber 128 is connected to a branch of theexhaust passageway and pipe 30, thence to the port 31 in the brakecylinder retainer device 32, the selector cock 34 of which is normallypositioned to connect said passageway and pipe 30 to the atmosphere byway of the port 35, so that normally the chamber 128 in the acceleratedrelease selector valve portion 115 will be at atmospheric pressure. Withchamber 128'in portion 115 at atmospheric pressure, when quick actionchamber fluid at normal brake pipe pressure is supplied to the chamber121, such pressure will be capable of moving the piston valve 119against opposition of the spring 127 to an accelerated service releaseposition defined by engagement of a member 131 of the diaphragm piston129 with a casing shoulder 132 to cause the groove 125 in piston valve119 to disestablish communication between passageway 28 and passageway118 while causing the groove 124 to communicate said passageway 118 withthe emergency reservoir passageway 20. t

' According to a feature of the invention, the pressure chamber 121 inthe accelerated release selector valve portion 115 is in constantly opencommunication with the quick action chamber 81 and with the chamber 79in the emergency application control portion 76 so that the pressure offluid in chamber 121 will vary correspondingly with quick action chamberpressure, and the value of the compression spring 127 is such that, whenchamber 128 is at atmospheric pressure by virtue of the direct ventposition of the selector cock 34 in the brake cylinder retainer device32 and the quick action chamber pressure as experienced in said chamber121 is at values corresponding to brake pipe pressures existent duringany degree of service application of the brakes, the pressure of fluidin chamber 121 will actuate and hold the piston valve 119 in itsaccelerated service release position, opposite to that in which it isshown in the drawing, against opposition of said spring 127 to maintainthe accelerated release supply passageway 118 connected to the emergencyreservoir passageway 20 by way of the groove 124 in said piston valve.When quick action chamber pressure in chamber 121 is subsequentlyreduced below some value, such as thirty-five pounds per square inch, avalue which is assuredly below any brake pipe pressure existent during aservice application of the brakes or, in other words, When quick actionchamber pressure in chamber 121 is reduced to a value which correspondsto a brake pipe pressure existent only during an emergency applicationof the brakes, then the spring 127 will cause the piston valve 119 toassume its accelerated emergency release position in which it is shownin the drawing, for connecting the accelerated release supplypassagewayllS to the brake cylinder passageway 28 via groove 125. If,however, the selector cock 34 in the retainer device 32 is set to retaina certain brake cylinder pressure during release of fluid under pressurefrom the brake cylinder device 2 by way of exhaust passageway 30 and theservice or triple valve portion 14, as by movement of said cock 34 to aposition for disconnecting said passageway 30 directly to the atmosphereand connecting it to the atmosphere instead by way of port 31,reoriented port 33 in cook 34, a passageway 133, a spring-loaded checkvalve assemblage 134 which will pass fluid at pressures only above acertain value such as ten or twenty pounds per square inch, and a ventport 135; then, when chamber 128 is pressurized via passageway 30 atretainer valve setting, piston valve 119 cannot be moved to itsaccelerated service release position by quick action chamber pressure inchamber 121, due to the adidtional opposition to such movement affordedby pressure of fluid in chamber 128 acting on the piston valve 119through the medium of the diaphragm piston 129 and the stem 130. 'If,during the release of fluid under pressure from the chamber 22 in thebrake cylinder device 2 by way of the service or triple valve portion 14and the exhaust passageway 30 as previously described, the chamber 128becomes pressurized, by virtue of position of retainer valve device 32,while piston valve 119 is in its accelerated service release positionopposite to that in which it is shown in the drawing, then pressure offluid thus built-up in chamber 128 will, in assist to spring 127, act onthe diaphragm piston 129 to return the piston valve 119 to itsaccelerated emergency release position in which it is shown in thedrawing, and prevent its return to accelerated service release positionuntil complete re lease of fluid under pressure from the chamber 128with return of the selector cock 34 in the retainer valve device 32 toits non-retaining position in which it is shown in the drawing forcomplete release of fluid under pressure from the passageway 30 to theatmosphere.

In the emergency application control portion 76, a portion of the slidevalve stem 83 extends slidably through a bore 136 for abuttingengagement with the accelerated release control check valve 117 which isurged towards its seated position by a compression spring 137; the endof the stem 83 in proximity to valve 117 being reduced in cross-sectionto provide an annular passageway 13% within the bore 136 and inencirclement of the stem to accommodate flow of fluid under pressurefrom the chamber 115 to the brake pipe passageway 9 by way of a passage-14 way 139 open to said passageway 138, and'a springloaded,back-flow-preventing check valve 140 having a light bias spring 141which requires an unseating differential in pressures across the checkvalve 141) of only several pounds per square inch.

Accelerated release operation following a service application of thebrakes According to the invention, during the previouslydescribedinitial charging of the equipment responsively to pressurization of thebrake pipe 1, fluid under pressure from the brake pipe 1 will flow byway of the brake pipe passageway 6, the strainer chamber 7, the brakepipe passageway 9, and the choke 82 into the quick action chamber 81,thence, by way of the passageway 80, such fluid under pressure will flowto the chambers 79 and 121 in the emergency application control portion76 and accelerated release selector valve portion 115, respectively, tocharge these chambers to normal, full-charge, brake pipe pressure ofsuch as the seventy pounds per square inch as herein previously chosenfor example. During such charging of the quick action chamber 81, thebrake pipe pressure in chamber 75 in the emergency application controlportion 76, due to the restriction imposed by the choke 82 to chargingof said quick action chamber with fluid under pressure from the brakepipe, will sufiiciently preponderate over the quick action chamberpressure in chamber 79 in said portion 76 to cause the diaphragm piston77 to unseat the accelerated release control check valve 117 through themedium of the slide valve stem 83 against opposition of the compressionspring 137 and to maintain suchcheck valve 117 unseated against actionof said spring substantially until quick action chamber pressureequalizes via choke 82 with brake pipe pressure subsequent to attainmentof its normal full-charge value. Such unseating of the check valve 117during initial charging of the quick action chamber 81 as describedabove will not result in flow of fluid under pressure from chamber 116to the brake pipe passageway 9 via the unseated check valve 117 however,since, at time of initial unseating of valve 117 the chamber 116 will beconnected to the atmosphere by way of the passageway 118, groove in thepiston valve 119 of the accelerated release selector valve portion 115,the brake cylinder passageway 28, the groove 29 in the main slide valve13 in the service or triple valve portion 14 which will be in itsrelease position in which it is shown in the drawing, and the exhaustpassageway 36; and subsequently, when chamber 1116 becomes connected tothe emergency reservoir 4 by quick-action-chamberpressure-responsivemovement of the piston valve 119 in the accelerated release selectorvalve portion 115, the pressure of fluid in the emergency reservoir willbe less than that in the brake pipe pressure inpassageway 9 andtherefore incapable of flow thereto.

During such charging of the quick action chamber 81 from the brake pipevia passageway 9 and the choke 82, should the quick action chamber 81become charged to a pressure above normal brake pipe pressure as aresult of charging of the brake pipe to such as main reservoir pressureon the locomotive, such overcharge of the quick action chamber 81 willbe rapidly dissipated to the brake pipe 1 upon subsequent return ofbrake pipe pressure to its normal full-charge value by way of the choke82 and brake pipe passageway 9 as well as by way of the passageway 80,the chamber 79 in the emergency application control portion 76, apassageway 142, a spring-biased, spill-over check valve 143, theemergency reservoir passageway 2t), the registering ports 19 and 17 inthe slide valves 13 and 18 in the service or triple valve portion 14which will be in its release position in which it is shown in thedrawing, the slide valve chamber 15 in said portion 14, the brake pipepassageway 11, the charging choke 19, the brake pipe passageway 9,strainer chamber 7 and the brake pipe passageway 6 connected to thebrake pipe 1.

Subsequent to initial charging of the equipment, and during theinitiation of a service application of the brakes as previouslydescribed responsively to reduction in brake pipe pressure at a servicerate up to the maximum degree of such as twenty pounds per square inchbelow the normal brake pipe pressure of such as seventy pounds persquare inch, the diaphragm piston '77 in the emergency applicationcontrol portion 76 will respond initially to such service reduction inbrake pipe pressure as experienced in its chamber 75 relative to quickaction chamber pressure in its chamber 79 to move the slide valve 84 toits position defined by engagement of the cage and return springassemblage 78 with the casing shoulder 111 for connecting the chamber 7to the exhaust passageway 114 by Way of the port 112 in said slide valve84 and the choke 113 to permit quick action chamber pressure to releaseto the atmosphere for reduction in pressure thereof corresponding to thereduction in brake pipe pressure at the service rate. During suchreduction in quick action chamber pressure corresponding to reduction inbrake pipe pressure during the eflecting of a service application of thebrakes, the quick action chamber pressure as experienced in the chamber121 in the accelerated release selector valve portion 115 will besuflicient to maintain the piston valve 119 disposed in its acceleratedservice release position against opposition of the spring 127 tomaintain the accelerated release supply passageway 113 connected to theemergency reservoir passageway it being appreciated that during suchservice reduction in brake pipe pressure, the service or triple valveportion 14 will respond to the reduction in brake pipe pressure aspreviously described to initiate quick serviceactivity, to effect supplyof fluid under pressure from the auxiliary reservoir to brake cylinderdevice 2, and to subsequently assume its lap position for holding suchpressure in the brake cylinder device upon termination of such servicereduction in brake pipe pressure for effecting a service application ofthe brakes. Finally, immediately upon completion of reduction in brakepipe pressure, the quick action chamber pressure as experienced in thechamber 79 in the emergency application control portion 76 will bemomentarily reduced, via port 112 in slide valve 84, below brake pipepressure existent in chamber 75 sulficiently to cause the diaphragmpiston 77 to move the slide valve 84 to a lap position in which it isshown in the drawing defined by engagement of the lowermost end of theslide valve stem 83 with the spring-loaded check valve 117. In such lapposition of the slide valve 84 the port 112 therein will be out ofregistry with the choke 113 and thereby with the exhaust passageway 114to prevent further reduction in quick action chamber pressure which willsubsequently equalize with that in brake pipe by way of the passageway80, choke 82, and the brake pipe passageway 9.

Subsequently, upon initiation of restoration in the brake pipe pressurefollowing a service application of the brakes, such initial increase inbrake pipe pressure will be experienced in the brake pipe pressurechamber 75 in the emergency application control portion 76 of the brakecontrolling valve device 5 on the first car or cars of the train, andwhen such brake pipe pressure in chamber 75 preponderates over quickaction chamber pressure in chamber 79 of said portion 76 to a slightextent of such as seven-tenths of a pound per square inch, the diaphragmpiston '77 will respond to unseat the accelerated release control checkvalve 117 through the medium of the slide valve stem 83 and permit fluidunder pressure to flow from the emergency reservoir 4 locally into thebraketpipe 1 for rapid equalization of pressures therebetween, by flowof fluid under pressure by Way of the emergency reservoir passageway 20,the groove 124 in piston valve 119 in the accelerated release selectorvalve portion 115, the accelerated release supply passageway 118, thechamber 116 and the unseated accelerated release control check valve 117in the emergency application control portion 76, the annular passageway138 also therein, the passageway 139, the lightly-biased antiback-flowcheck valve 140, the brake pipe passageway 9, the strainer chamber 7,and the brake pipe passageway 6.

Immediately prior to the admission of fluid under pressure from theemergency reservoir 4 locally to the brake pipe 1 on a particular car byway of the accelerated release selector valve portion and the emergencyapplication control portion 76 as above described, the emergencyreservoir pressure as bottled up by the service or triple valve portion14 in its lap position will be at normal full charge brake pipe pressureof such as seventy pounds per square inch; pressure of fluid in thebrake pipe 1 will be at a pressure corresponding to that resultant fromthe effecting of a service reduction in the brake pipe pressure forrealization of the service application of the brakes, but no less thansuch as fifty pounds per square inch which corresponds to a full servicereduction in brake pipe pressure below a normal full charge brake pipepressure of seventy pounds per square inch; and pressure of fluid in theauxiliary reservoir 3 will be substantially equal to that in the brakecylinder pressure chamber 22 in the brake cylinder device 2 by virtue ofprevious equalization therewith during the effecting of the serviceapplication of the brakes, and such auxiliary reservoir and brakecylinder pressure in turn will be only slightly less than brake pipepressure by the extent necessary to have caused the diaphragm piston 36in the service or triple valve portion 14 to actuate the auxiliary slidevalve 18 to its position for lapping off the service port 49 in the mainslide valve 13 to the slide valve chamber 15 open to the auxiliaryreservoir, as will be appreciated from previous description. Thus, forexample, during the existence of a full service application of thebrakes, pressure of fluid in the emergency reservoir 4 may be at such asseventy pounds per square inch, pressure of fluid in the brake pipe 1may be at such as fifty pounds per square inch, and pressure of fluid inthe brake cylinder pressure chamber 22 in the brake cylinder device 2and in the auxiliary reservoir 3'will be at such as fifty pounds persquare inch, less the necessary slight preponderance in brake pipepressure required to move the service or triple valve portion 14 to itslap position. Where, as in the usual fluid pressure railway brakeapparatus employed in the United States, the volume of the emergencyreservoir 4 in the brake apparatus on any particular car is about threeand one-half times the volume of the brake pipe on such car, with suchpressure relationships existing as set forth above, then, uponequalization of pressure of fluid in the emergency reservoir 4 with thatin the brake pipe 1 on the particular car by way of the acceleratedrelease selector valve portion 115 and the emergency application controlportion 76 of the respective brake controlling valve device 5 responsiveto initiation of brake pipe pressure restoration following a serviceapplication of the brakes as previously described, pressure of fluid inthe emergency reservoir 4 will equalize into the brake pipe 1 on suchcar at about sixty-four pounds per square inch. Such brake pipe pressureof sixty-four pounds per square inch as experienced in the brake pipepressure chamber 38 in the service or triple valve portion 14 of suchbrake controlling valve device 5, being some fourteen pounds per squareinch greater than auxiliary reservoir pressure in the slide valvechamber 15 of said portion 14, will be more than ample to cause saidservice or triple valve portion to assume its release position in whichit is shown in the drawing for releasing fluid under pressure from thebrake cylinder pressure chamber 22 in the respective brake cylinderdevice 2 as previously described herein for releasing the serviceapplication of brakes on such car. Immediately upon the service ortriple valve portion 14 thus assuming its release position in which itis shown in the drawing, the pressure of fluid in the emergencyreservoir 4, being higher than the auxiliary reservoir pressure, willtend to equalize with auxiliary reservoir pressure by Way of theemergency reservoir passageway and pipe 20, the registered ports 19 and17 in the slide valves 13 and 18 in said service or triple valve portion14, the slide valve chamber 15 therein, and the passageway and pipe 16.

The equalization pressure resultant from such flow from the emergencyreservoir 4 to the auxiliary reservoir 3 as experienced in chamber 15 inthe triple valve portion 14, however, will not be as high as the brakepipe pressure in chamber 38 existent at that time, due to the ratio ofthe volumes of the two reservoirs, a ratio usually of approximately oneand four-tenths to one in the direct release type brake equipmentsemployed in the United States. For example, where such ratio ofemergency reservoir volume to auxiliary reservoir volume exists and thebrake pipe and emergency reservoir pressures following a full serviceapplication of the brakes are such as sixty-four and sixty-six poundsper square inch, respectively, immediately after equalization of theemergency reservoir with the brake pipe by way of the emergencyapplication control portion 76 and the spring-biased check valve 140 aspreviously described, then the emergency reservoir 4 might equalize withthe auxiliary reservoir 3 at such as fifty-nine pounds per square inchby way of the slide valve chamber 15 in the triple valve portion 14-when it assumes its service position, and such resultant pressure offifty-nine pounds per square inch in slide valve chamber 15 is incapableof causing said triple valve portion to leave its service positionagainst opposition of the sixty-four pounds per square inch of brakepipe pressure in chamber 38. Similar circumstances prevail during anydegree of service application of the brakes.

Following such equalization of emergency reservoir pressure with that inthe auxiliary reservoir 3, or/and coincident therewith, pressure offluid in the brake pipe 1 will flow via brake pipe passageway 9,charging choke it}, charging passageway 11, port 12 in slide valve 14 tothe slide valve chamber 15 in triple valve portion 14, thence, by way ofthe passageway and pipe 16, to the auxiliary reservoir 3 to rechargesame, and, via port 17 in the slide valve 18, port 19 in the slide valve13, and the passage and pipe 20, to the emergency reservoir 4 for itsrecharge, as brake pipe pressure is increased to its normal full-chargevalue of such as seventy pounds per square inch by Way of the engineersbrake valve on the locomotive.

At the same time, such substantially immediate increase inpressurization of the brake pipe 1 on the particular car, resultant fromsupply of fluid under pressure thereto from the emergency reservoir 4via the emergency application control portion 76 in response toinitiation in brake pipe pressure restoration following a serviceapplication of the brakes as described, is propagated via the brake pipe1 to the brake controlling valve device on the next car of the train tocause operation of its emergency application control portion 76 toequalize" its emergency reservoir 4 locally with the brake pipe 1 onsuch car and to thereby cause the respective triple valve portion 14 toassume its release position for release of the service application ofthe brakes on such car, and so on serially from car to car back throughthe train.

By virtue of the accelerated release feature of applicants directrelease type brake control apparatus as disclosed herein, it has beendemonstrated on a test rack composed of a number of brake apparatusesembodying said accelerated release feature, arranged to duplicateoperation in a train, that the release transmission time on a trainsimilarly equipped can be greatly reduced below that on trains of equallength employing conventional brake apparatuses not embodying suchaccelerated release feature. For example, rack tests indicate that,during brake release following a service application of the brakes, therelease transmission time on a train of one hundred fifty cars eachequipped with a brake apparatus embodying applicants accelerated releasefeature, will be less than one-fifth of that required for a train ofequivalent length equipped exclusively with conventional directreleasetype brake apparatuses. Moreover, rack tests indicate that byinterposing cars employing applicants accelerated release equipment atcertain intervals in a train between cars equipped with such as thewell-known AB brake valves, the resultant local build-up in brake pipepressure at such intervals can be propagated through the brake pipe onthe AB equipped cars to hasten the brake release propagation time ofsuch train.

If, at the time that the emergency application control portion 76 in therespective brake controlling valve device 5 unseats the acceleratedrelease control check valve 117 responsively to restoration of brakepipe pressure following a service application of the brakes, the pistonvalve 119 in the accelerated release selector valve portion 115 is inits uppermost position in which it is shown in the drawing as a resultof pressurization of chamber 328 by retainer valve retention duringcycling operation of the brakes on the train, for example, then, sincechamher 116 at the input side of the unseated accelerated releasecontrol check valve 117 is disconnected from the emergency reservoir 4and connected instead, by the groove 125 in said piston valve 119, tothe brake cylinder pressure chamber 22 which at this time will beslightly less than brake pipe pressure, according to a feature of theinvention, there will be no flow into the brake pipe by way of theunseated check valve 117 for acceleration of brake release, and theemergency reservoir pressure will not be depleted, but rather will bekept in reserve for emergency use, if it becomes necessary, for example,due to depletion of fluid under pressure from the auxiliary reservoirwith too frequent alterations in application and release of the brakesduring such cycling.

At each brake controlling valve device 5 following restoration of brakepipe pressure to its normal fullcharge value of such as seventy poundsper square inch subsequent to accelerated release of a serviceapplication of the brakes as described in the preceding paragraphs,quick action chamber pressure as experienced in chamber 79 in theemergency application control portion 76 will equalize with brake pipepressure in the chamber 75 of said portion 76, by way of the brake pipepassageway 9, the choke 82, and the passageway 80, and such equalizationof pressures on opposite sides of the diaphragm piston 77 will permitthe spring 137 to seat the accelerated release control check valve117and return the slide valve stem 83, the slide valve 84 and saiddiaphragm piston to their respective positions in which they are shownin the drawing.

Accelerated release operation following emergency application 0 thebrakes During the elfecting of an emergency application of the brakes aspreviously described herein, as brake pipe pressure is suddenly reducedto that of the atmosphere the quick action chamber pressure iscorrespondingly reduced by flow of fluid under pressure from the chamber79 in the emergency application control portion 76 by way of the port 85in the slide valve 84 in its emergency application position, as will beappreciated from such previous description, the passageway 86, theblow-down timing choke associated with the emergency vent valve portion,passageway 106 and port 108 of said portion 89, and the large-capacityvent passageway 96.

When the quick action chamber pressure as experienced in the chamber 121in the accelerated release selector valve portion is thus reduced belowsuch as thirtyfive pounds per square inch, the spring 127 in saidportion 115 will actuate the piston valve 119 from its lowermost oraccelerated service release position, opposite to that in which it isshown in the drawing and which it occupies during existence of a serviceapplication of brakes, to its accelerated emergency release position, inwhich it is shown and which is defined by engagement of the uppermostend of said piston valve 119 with the casing shoulder 126, to connectthe brake cylinder passageway 28 to the chamber 116 at the input side ofthe accelerated release control check valve 117, by way of thepassageway 118 and the groove 125 in said piston valve 119.

While the emergency application of the brakes remains in effect, thequick action chamber will remain at atmospheric pressure alongwithpressure of fiuid in the brake pipe, and such quick action chamberpressure as experienced in the chamber 121 in the accelerated releaseselector valve portion 115 will permit the piston valve 119 therein toremain in its accelerated emergency release position, while theequalization between brake pipe pressure in chamber 75 and quick actionchamber pressure in chamber 79 in the emergency application controlportion 76 at opposite sides of the diaphragm piston 77 permits the cageand spring assemblage 78, previously held in compression, to move theslide valve 84 through the medium of the stem 83 to its breatherposition in which said chamber 79 is connected to the atmosphere by wayof the slide valve port 112, the choke 113, the passageway 114 and thelarge capacity vent passageway 96. Also during the existence of suchemergency application of the brakes, from the previous description inconnection with the efiecting of such emergency application, it will beappreciated that the pressure of fluid in the auxiliary reservoir 3 andin the emergency reservoir 4 will have equalized with that in the brakecylinder pressure chamber 22 at such as sixty or sixty-one pounds persquare inch, for example, while the brake pipe is at atmosphericpressure, and therefore, as a result of the continued preponderance ofauxiliary reservoir pressure as experienced in the slide valve chamberin the service or triple valve portion 14 over brake pipe pressure asexperienced in the chamber 38 in said portion, such preponderance willmaintain the service or triple valve portion in its application positionin which said auxiliary reservoir 3 is maintained connected to the brakecylinder passageway 28 via said slide valve chamber 15 and the serviceport 49 in the main slide valve 13 of said triple valve portion. It willalso be appreciated, that, during the existence of an emergencyapplication of the brakes, the vent valve 99 in the emergency vent valveportion 89 'will have returned to and will remain in its closed positionin which it is shown in the drawing.

Upon initiation of brake pipe pressure restoration following anemergency application of the brakes by a supply of fluid under pressureto the brake pipe via the engineers 'brake valve device on thelocomotive, the brake pipe pressure as experienced in chamber 101 willcause the piston valve 102 in high pressure valve portion 93 to returnand remain in the position in which it is shown in the drawing fordisestablishing communication between the emergency reservoir passagewayand the brake cylinder passageway 28 via the groove 104, while, byvirtue ,of the restriction presented by choke 82 to recharging of thequick action chamber 81 and the combined capacity of said chamber 81with that in the chamber 79 in the emergency application control portion76, the brake pipe pressure as experienced in chamber 75 in said portion76 will quickly be made to preponderate over quick action chamberpressure 79 sufficiently to cause the diaphragm piston 77 to move theslide valve 84 to a position ,for blanking otf the exhaust choke 113 tosaid chamber 79 and to cause stem 83 to unseat the accelerated releasecontrol check valve 117 against opposition of the spring 137 to permitsubstantial equilization flow of fluid under pressure to the brake pipe,from the brake cylinder pressure chamber 22 and the auxiliary reservoir3. Such equalization flow to the brake pipe for pressurizing same \willoccur by way of the brake pipe passageway 9, the lightly spring-biasedanti-back-flow check valve 140, the

passageway 139, the annular passageway 138 in the emergency applicationcontrol portion 76, the unseated accelerated release control check valve117 and the chamber 116 also in said portion 76, the passageway 118, thegroove 125 in the piston valve 119 in the accelerated release selectorvalve portion 115, and the brake cylinder passageway 28 which isconnected at this time to the auxiliary reservoir 3 by way of theservice port 49 in the slide valve 13 in the service or triple valveportion 14, slide valve chamber 15 therein, and the passageway and pipe16, and which is at the same time connected to brake cylinder pressurechamber 22 by way of the unseated check valve 27 and the chamber 25 inthe brake cylinder inshot and quick service limiting portion 26, and thepassageway and pipe 24.

Such equalization in pressures between the brake pipe 1, the brakecylinder pressure chamber 22 and the auxiliary reservoir 3 will resultin a rapid increase in brake pipe pressure on the first car in the trainfrom atmospheric pressure to such as forty-five pounds per square inch,while the pressure of fluid in the auxilary reservoir and in brakecylinder pressure chamber 22 Will reduce to such as forty-seven poundsper square inch, and the emergency reservoir at this time remains at apressure of such as sixty pounds per square inch. Such localpressurization of the brake pipe on the first car of the train byequalization of the auxiliary reservoir 3 and the brake cylinderpressure chambers 22 into the brake pipe 1 will cause suflicientpressurization of the brake pipe pressure chamber in the emergencyapplication control portion 76 in the corresponding brake controllingvalve device or devices 5 on the succeeding car or cars in the train toactuate the respective accelerated release control check valve or valves117 as the case may be to cause a similar local pressure equalization ofthe respective brake cylinder pressure chambers and auxiliary reservoirslocally with that in the brake pipe 1 for rapid pressurization of sameto a considerable degree, and so on serially back' through the train.

Meanwhile, in the brake controlling valve device 5 on each car in whichsuch pressure equalization of the auxiliary reservoir and brake cylinderwith the brake pipe is occurring, the quick action chamber pressure willbe built up from the brake pipe 1 by way of brake pipe passageway 9 andthe choke 82, which choke maintains suflicient differential betweenbrake pipe pressure as experienced in chambers 75 in the emergencyapplication control portion 76 and the quick action chamber pressure asexperienced in the chamber 79 in said portion 76 to hold the acceleratedrelease control check valve 117 unseated. Following such pressureequalization of the brake cylinder pressure chamber 22 and the auxiliaryreservoir 3 with the brake pipe 1, the quick action chamber pressureWill be increased as above sulficiently to move the piston valve 119 inthe accelerated release selector valve portion downwardly as viewed inthe drawing to its accelerated service release position to connect theemergency reservoir at such as sixty pounds per square inch with thebrake pipe 1 at such as forty-five pounds per square inch, or higher asa result of flow of fluid under pressure thereto by the engineers brakevalve on the locomotive, by way of the emergency reservoir pipe andpassageway 20, the groove 124 in said piston valve 119, the passageway118, the chamber 116, the unseated accelerated release control checkvalve 117, the annular passageway 138, the passageway 139, the lightlyspringbiased anti-back-flow check valve 140, the brake pipe passageway9, the strainer chamber 7 and the brake pipe passageway 6.

As a result of such equalization of the emergency reservoir 4 into thebrake pipe 1, pressure of fluid in the brake pipe will suddenly beincreased from such as fortyfive or so pounds per square inch to a valuein excess of fifty-eight pounds per square inch, and such brake pipe qpressure in excess of fifty-eight pounds per square inch as thussuddenly experienced in the brake pipe pressure chamber 38 in theservice or triple valve portion 14 will sufficiently preponderate overthe auxiliary reservoir pressure at forty-seven pounds per square inchin the slide valve chamber 15 to cause the service or triple valveportion 14 to assume its release position in which it is shown in thedrawing for elfecting a release of fluid under pressure from the brakecylinder pressure chamber 22 in the brake cylinder device 2 aspreviously described herein.

Upon movement of the service or triple valve portion 14 to its releaseposition in which it is shown in the drawing as above mentioned, theemergency reservoir 4 at such as fifty-eight pounds per square inch willtend to equalize with the auxiliary reservoir at such as fortysevenpounds per square inch by way of the passageway and pipe 20 and theports 19 and 17 in the slide valves 13 and 18 in said triple valveportion 14, the slide valve chamber 15, and the passageway and pipe 16,but such equalization, even if realized, irrespective of the fact thatsuch ports 17 and 19 are of somewhat limited capacity, could result onlyin an equalization pressure in said chamber 15 of such as fifty-threepounds per square inch, a pressure incapable of overcoming opposition ofthe brake pipe pressure in chamber 38 and causing the service valveportion 14 to assume its quick service position. 7

Subsequent to pressure equalization of the auxiliary reservoir 3 and thebrake cylinder pressure chamber 22 on a particular car of a train withthe brake pipe 1 on such car, and subsequently, of the emergencyreservoir 4 with said brake pipe 1, the pressure of fluid in the brakepipe will be increased via the engineers brake valve on the locomotiveto its normal full charge value of such as seventy pounds per squareinch for recharging the auxiliary and emergency reservoirs 3 and 4 tothe same value by way of the service or triple valve portion 14 of therespective brake controlling valve device 5 as previously described.Pressure of fluid in the quick action chamber 81 also attains suchnormal full-charge value by virtue of charging flow from brake pipe 1 byway of passageway 9 and the coke 82, and when, during its build-up, thequick action chamber pressure as experienced in the chamber 79 in theemergency application portion 76 increases to within a slight degreeless than normal brake pipe pressure existent in the chamber 75, thespring 137 acting on the check valve 117 will reseat same and causeactuation of the slide valve 84 and piston diaphragm '77 to therespective positions in which they are shown in the drawing, inpreparation for subsequent activity upon reapplication of brakes.

Summary From the foregoing description of applicants improveddirect-release type brake apparatus for use on railway cars, it will beapparent that, according to novel features of such apparatus, release ofthe brakes following both a service application and an emergencyapplication thereof is greatly accelerated. In connection withaccelerated release following a service application of the brakes, suchfeatures is realized to great advantage on long trains where suchaccelerated release of the brakes, in reducing the release propagationtime through the train, enables brakes on the train to be released whilethe train is still in motion, without danger of break-in-two betweencars somewhere in the train, thereby greatly facilitating expeditioustransportation of such train.

Having now described the invention, what we claim as new and desire tosecure by Letters Patent, is:

1. In a fluid pressure brake apparatus, in combination, a normallycharged brake pipe; a brake cylinder device; a normally chargedauxiliary reservoir; a normally charged supplemental reservoir; servicevalve means controlling supply and release of auxiliary reservoir fluidunder pressure to and from said brake cylinder device responsively toreduction and restoration of brake pipe pressure; an accelerated releasesupply chamber; an accelerated release control valve controllingcommunication between said accelerated release supply chamber and saidbrake pipe; a selector valve operable to selectively establishcommunication between said accelerated release supply chamber and saidsupplemental reservoir or between said accelerated release supplychamber and said brake cylinder device and said auxiliary reservoir; andmeans controlled by brake pipe pressure and controlling operation ofsaid accelerated release control valve and of said selector valve toeifect supply of fluid under pressure to said brake pipe from saidsupplemental reservoir upon initiation of brake pipe pressurerestoration following a \service reduction in brake pipe pressure and toeffect supply of fluid under pressure to said brake pipe from said brakecylinder device and said auxiliary reservoir upon initiation of brakepipe pressure restoration following an emergency reduction in brake pipepressure.

2. In a fluid pressure brake apparatus, a normally charged brake pipe, abrake cylinder device, a normally charged auxiliary reservoir, anormally charged emergency reservoir, service valve means operative uponreduction in brake pipe pressure relative to auxiliary reservoirpressure to establish a service supply communication between saidauxiliary reservoir and said brake cylinder device, operative uponsubstantial equalization of auxiliary reservoir pressure with brake pipepressure to close said service supply communication, and operative uponsubsequent preponderance in brake pipe pressure over auxiliary reservoirpressure to establish a brake cylinder exhaust communication for ventingfluid under pressure from said brake cylinder device, emergency controlvalve means operative upon reduction in brake pipe pressure at anemergency rate to establish an emergency supply communication betweensaid emergency reservoir and said brake cylinder device and operative toclose said emergency supply communication upon subsequent initiation ofbrake pipe pressure restoration, one-way flow valve means having aninlet for admission of fluid under pressure and an outlet open to saidbrake pipe, an accelerated release supply passageway, acceleratedrelease selector means automatically operative to connect saidaccelerated release. supply passageway selectively to said service:supply communication or to said emergency reservoir according towhether or not, respectively, an emergency reduction in brake pipepressure has been effected, and accelerated release control meansoperative to connect said accelerated release supply passageway to theinlet of said one-way-flow valve means upon initiation of brake pipepressure restoration following an application of the brakes.

3. The combination as set forth in claim 2, further including retainervalve means selectively positionable to permit either complete orpartial release of fluid under pressure from said brake cylinder devicevia said exhaust communication when established by said brakecontrolling means following a brake application, and means controlled bypressure of fluid in said exhaust communication to prevent flow of fluidunder pressure from said accelerated release supply passageway to saidbrake pipe via said oneway-flow valve means when brake cylinder pressureis being retained by said retainer valve means.

4. In a fluid pressure brake apparatus, in combination, a brake pipe; abrake cylinder device; an auxiliary reservoir; an emergency reservoir;triple valve means responsive to preponderance in brake pipe pressureover auxiliary reservoir pressure and vice vensa to selectively opensaid brake cylinder device to the atmosphere, and to said auxiliaryreservoir, respectively, and to restrictedly open and to close,respectively, the auxiliary and emergency reservoirs to said brake pipe;high pressure valve means responsive to preponderance in pressure offluid in a high pressure valve control chamber over brake pipe pressureand vice versa to open and close, respectively, said brake cylinderdevice to said emergency reservoir;

vent valve means operable responsively to pressure of fluid in a ventvalve control chamber above and below a certain value to open and close,respectively, said brake pipe locally to the atmosphere; a restrictedblowdown communication constantly connecting the high pressure and ventvalve control chambers to the atmosphere; antiback-flow check valvemeans having an inlet to receive fluid under pressure and having anoutlet constantly open to said brake pipe; a quick action chamber inconstantly open restricted communication with said brake pipe; anaccelerated release supply passageway; control means responsive toreduction in brake pipe pressure at a service rate to effect asimultaneous corresponding reduction in quick action chamber pressure,responsive to reduction in brake pipe pressure at a rate greater thansaid service rate to prevent said simultaneous corresponding reductionin quick action chamber pressure and to connect said quick actionchamber to the high pressure and vent valve control chambers foreffecting operation of the high pressure and vent valve means,responsive to subsequent stabilization of brake pipe pressure followingservice and emergency reductions in such pressure to close said quickaction chamber to the high pressure and vent valve control chambers, andresponsive subsequently to initiation in brake pipe pressure restorationto open said accelerated release supply passageway to the inlet of saidanti-backflow check valve means; and accelerated release selector valvemeans responsive to quick action chamber pressures above and below avalue corresponding to a brake pipe pressure existent only during anemergency application of the brakes, to selectively connect saidaccelerated release supply passageway to said emergency reservoir and,to said brake cylinder device, respectively.

5. The combination as set forth in claim 4, further characterized inthat said control means comprises an accelerated release control checkvalve biased toward a closed position; a slide valve having a breatherport constantly open to said quick action chamber and adapted forregistry with a restricted vent port to the atmosphere and having a highpressure and vent valve control port also, constantly open to said quickaction chamber and adapted for registry with a supply port open to thehigh pressure and vent valve control chambers; a caged springassemblage; and a movable abutment subiect opposingly to. brake pipe andquick action chamber pressures operatively connected to a stem foractuating said slide valve and said accelerated release control checkvalve, said movable abutment being normally positioned While brake pipeand quick action chamber pressures are at a normal full-charge value tomaintain the breather and control ports in said slide valve closed tothe restricted vent and, supply ports, respectively, and to maintainsaid accelerated release control check valve closed, said movableabutment being responsive to a reduction in brake pressure relative toquick action chamber pressure to actuate said slide valve to registersaid breather port with said restricted vent port for equalizing quickaction chamber pressure with brake pipe pressure when same is reducingat a service rate and to further actuate, against opposition of saidcaged spring assemblage, said slide valve to close said restricted ventport and register said control port with said supply port when brakepipe pressure is reducing at an emergency rate, said movable abutmentbeing responsive to subsequent equalization in brake pipe and quickaction chamber pressures to permit said caged spring assemblage toactuate said slide valve to its position for registry of its. breatherport with said restricted vent port while blanking off its control port,said movable abutment being responsive to subsequent preponderance inbrake pipe pressure over quick action chamber pressure to open saidaccelerated release control check valve while the breather and controlports in said slide valve remain blanked off to the vent and supplyports, respectively, and said movable abutment means being responsive tosubsequent substantial equalization in quick action chamber pressurewith brake pipe pressure to move to permit said accelerated releasecontrol check valve to reclose while the breather and control ports insaid slide valve remain blanked 01f to the vent and supply ports,respectively.

6. In a fluid pressure brake apparatus, in combination, a normallycharged brake pipe, a normally charged emergency reservoir, meansdefining an accelerated release communication for conveying fluid underpressure from said emergency reservoir to said brake pipe, anaccelerated release control check valve biased toward a seated positionfor normally closing said accelerated release com- 'rnunication, a quickaction chamber normally charged to the normal charge value of brake pipepressure, normally closed breather control valve means controllingconnection of said quick action chamber with the atmosphere, actuatingstern means for actuating said breather control valve means and forengaging said accelerated release control check valve to unseat same, amovable abutment subject opposingly to brake pipe and quick actionchamber pressures and; operatively connected to said actuating sternmeans and responsive to a service rate of reduction in brake pipepressure relative to quick action chamber pressure for opening saidbreather control valve means to effect reduction in quick action chamberpressure to substantially the same value as the reduced brake pipepressure while said accelerated release control check valve remainsseated, and responsive to a subsequent slight increase in brake pipepressure above quick action chamber pressure to unseat said acceleratedrelease control check valve for opening said accelerated releasecommunication.

References Cited in the file of this patent UNITED STATES PATENTS1,438,317 Lewis Dec. 12, 1922 1,585,774 Farmer May 25, 1926 1,842,519Farmer Jan. 26, 1932 1,919,401 Thomas July 25, 1933 1,942,503 WhitakerJan. 9, 1934

